Louis Adolf Peter, 1st Prince of Sayn-Wittgenstein-Ludwigsburg-Berleburg, better known as Peter Wittgenstein in English, was a prince of the German dynasty of Sayn-Wittgenstein and field marshal in the Imperial Russian Army during the Napoleonic Wars. He was nicknamed the Saviour of Saint-Petersburg.

Field marshal was, with the exception of Generalissimo, the highest military rank of the Russian Empire. It was a military rank of the 1st class in the Imperial Russian Army and equal to those of Chancellor and Active Privy Councillor, 1st class in civil service, and General Admiral in the Imperial Russian Navy. After the Russian Revolution of 1917 the rank was abolished, alongside the Table of Ranks. In 1935 however, the Red Army introduced the equivalent rank of "Marshal of the Soviet Union" as the highest military rank of the Soviet Union, when ranks were restored under Stalin's rule.